Dimethyl maleate, physical properties

These two compounds, ( )-and (E)-dimethyl but-2-enedioate, are commonly known as dimethyl maleate and dimethyl fumarate. They provide a tel ling exam pie of how different the physical properties of geometrical isomers... 

Physical Properties of Thiazoles.—An X-ray crystallographic study of the cycloadducts formed from anhydro-4-hydroxythiazolium hydroxide and dimethyl maleate and dimethyl fumarate indicates that the dipole and dipolarophile approach in an exo manner, which can be accounted for by steric effects.A comparison of the melting and clearing points of various 2,4- and 2,5-disub-stituted thiazoles indicated that the former exhibited no mesophases whilst in certain cases the latter show liquid-crystalline properties. The exchange... 

Dimethyl maleate (9) and dimethyl fumarate (10) are examples of cis and trans isomers, called geometric isomers. Their names do not reflect this isomeric relationship, however, because the parent diacids from which they can be prepared were discovered and named before this stereochemical fact was known. Being diastereomers, these diesters would be expected to have different physical and chemical properties, and indeed they do. The difference in their physical states at room temperature is the most dramatic The maleate 9 is a liquid with a freezing point of about -19 °C, whereas the fumarate 10 is a solid with a melting point of 103-104 °C. 

Poly(vinyl acetate-co-dibutyl maleate), 277 Poly(vinyl acetate-co-diisobutyl maleate), 277 Poly(vinyl acetate-co-dimethyl maleate), 265 Poly(vinyl acetate-co-dipropyl maleate), 277 Poly(vinyl acetate-co-MA), 276 anhydride level determination, 441 applications, 277, 442, 649 chemical and physical properties, 276 grafted to polychloroprene, 471 process patents, 649... 

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